Turf maintenance machine

ABSTRACT

A turf maintenance machine comprising a vehicle having a front frame portion supported on a pair of wheels and a rear frame portion supported on a pair of drive wheels, said front frame portion being connected to the rear frame portion for pivotal movement relative thereto about a generally vertical steering axis. The two front wheels are mounted on the front frame portion for limited pivotal movement about an axis entending longitudinally of said machine and perpendicular to and below the rotational axis of the front wheels. A front, central reel is mounted on the front frame for pivotal movement relative to the front frame portion about a generally vertical axis spaced forwardly of said steering axis. A steering wheel is drivingly connected to the front frame portion by one transmission system and to the central reel by another transmission system such that the central reel turns relative to the front frame portion during steering to keep a generally constant overlap. Two side reels are connected to the front frame portion for pivotal movement therewith about said steering axis. The front reel and the side reels are mounted for pivotal movement about a forwardly and horizontally extending first axis as well as a laterally extending second axis perpendicular to the first axis to follow the terrain.

United States Patent [1 1 Sorenson et a1.

[ TURF MAINTENANCE MACK- ENE [75] Inventors: Charles E. Sorenson, MountVernon; Clyde I). Stubblefield; Arnold A. DeBaillie, both of Evansville,all of lnd.; Robert K. Bramley, Cleve1and;' Hugh A. Bourassa, UniversityHeights, both of Ohio [73] Assignee: Hahn, Inc., Evansville, Ind.

[22] Filed: Jan. 25, 1972 [21] Appl. No.2 220,629

[52] US. Cl 56/7, 56/14.7, 56/DIG. 22,

180/27 [51] Int. Cl A01d'75/30 [58] Field of Search 56/6, 7, 10.8, 11.3,

[56] References Cited UNITED STATES PATENTS 2,909,882 l0/1959 Lewis 56/73,060,818 10/1962 Roberts 180/20 3,616,626 10/1971 Bramley et al.. 56/72,899,793 8/1959 Swicher 56/1 14.7 3,058,281 10/1962 Lewis... 56/73,599,406 8/1971 Akgulian 56/DlG. 22

atee,

[ Nov. 113, 1973 Primary Examiner-Antonio F. Guida Att0rneyWilliam R.Coffey [57] ABSTRACT A turf maintenance machine comprising a vehiclehaving a front frame portion supported on a pair of wheels and a rearframe portion supported on a pair of drive wheels, said front frameportion being connected to the rear frame portion for pivotal movementrelative thereto about a generally vertical steering axis. The two frontwheels are mounted on the front frame portion for limited pivotalmovement about an axis entending longitudinally of said machine andperpendicular to and below the rotational axis of the front wheels. Afront, central reel is mounted on the front frame for pivotal movementrelative to the front frame portion about a generally vertical axisspaced forwardly of said steering axis. A steering wheel is drivinglyconnected to the front frame portion by one transmission system and tothe central reel by another transmission system such that the centralreel turns relative to the front frame portion during steering to keep agenerally constant overlap. Two side reels are connected to the frontframe portion for pivotal movement therewith about said steering axis.The front reel and the side reels are mounted for pivotal movement abouta forwardly and horizontally extending first axis as well as a laterallyextending second axis perpendicular to the first axis to follow theterrain.

31 Claims, 8 Drawing Figures PATENTEUHM 13 i975 SHEET 10F 5 PATENTEDnuv13 I973 3,7?L296 SHEU s or 5 TURF MAINTENANCE MACHINE It is a primaryobject of the present invention to provide a turf maintenance machinewhich is particularly suited for mowing and maintaining golf greens. Itwill be appreciated that very exacting grass maintenance is required inthe maintenance of golf greens. A primary object of the presentinvention is to provide such a machine which will rapidly cut andmaintain a golf green and yet do the job in as exacting manner as can beaccomplished by an individual painstakingly using a small lawn mower.The machine of the present invention is constructed and arranged suchthat relatively large or wide cutting paths can be achieved withoutdamage to the green.

DESCRIPTION OF THE PRIOR ART In the past, most machines capable ofcutting relatively wide strips of grass have not been particularlysuited for maintaining golf greens. The maintaining of golf greensrequires a machine with very exacting controls. In the past, machinescapable of cutting relatively wide strips have not included suchcontrols. For instance, to our knowledge, existing machines have notincluded means for carefully controlling the number of clips per inchwhich is the factor controlling the smoothness of greens. Further,existing machines have not included means for steering reel assembliesrelative to the vehicle to minimize cutting overlaps. Still further,existing machines-have not been provided with suitable means permittingthe reel assemblies to articulate independently to follow the terrain.

SUMMARY OF THE INVENTION One object of the present invention is toprovide a turf maintenance machine comprising a rear frame portionsuitably mounted on drive wheels and on which the engine, transmissionfor the drive wheels, fuel tanks, hydraulic tanks and pumps, and seatfor the rideroperator are mounted and a front frame portion supported onfront wheel means and on which the reels are mounted, the front frameportion being connected to the rear frame portion for pivotal movementrelative front wheels are able to pivot independently about generallyhorizontally extending axes extending in the direction of movement ofthe machine to follow the terrain. The rear frame portion, therefore, isthe heavier drive portion of the machine while the front frame portionis the lighter and more maneuverable portion of the machine. The frontframe portion, which carries the reels, is the steering portion of thevehicle.

Another object is to provide such a machine including a central reeldisposed forwardly of the front frame portion and left and right reelsdisposed, respectively, at the left and right hand sides of the frontframe portion, the left and right wheels being supported on the frontframe portion for pivotal movement therewith about the generallyvertical steering axis, and the central reel being supported on thefront frame portion for pivotal movement about a generally vertical axisdisposed forwardly of the said steering axis. Then, the support for thecentral reel is independently connected to the steering shaft so thatthe reels have a different steering ratio to maintain a generallyconstant cutting overlap.

Still another object of the present invention is to provide such amachine including a driven shaft on the rear frame portion with aflexible cable drive for each reel, the distal end of each cable drivebeing drivingly connected to its associated reel and the proximal end ofeach cable drive being drivingly connected to the said driven shaft bymeans of an electrically-operated clutch.

Yet another object of the present invention is to provide such a machineincluding a fluid-operated power cylinder for moving each reel betweenits operating position and retracted position, a control valvedominating each cylinder, a master valve dominating the control valvesand controlling the flow of fluid to said valves, a control switch foreach electrically operated clutch, and a master switch dominating thecontrol switches and controlling the flow of current to said controlswitches. Each control switch for a clutch is preferably operativelyconnected to its associated control valve to be operated by operation ofthe control valve, and the master switch is preferably operativelyconnected to the master valve to be operated by operation of the mastervalve. The control valves are used selectively to determine which of thethree reels will be moved to their operative position. Operation of acontrol valve permits operation of the cylinder controlled thereby and,at the same time, permits energization of the clutch controlled by theassociated control switch. The master valve is arranged so that theoperator of the machine can, by operating the master valve, move theselected reels to their operative position and, at the same time,provide current to energize the clutches associated with the selectedreels.

Another object of the present invention is to provide such a machineincluding a selectively variable transmission for drivingly connectingthe engine to the rear drive wheels so that the speed of the said drivenshaft to which the cable drives are connected is independent from theground speed of the vehicle.

Yet another object of the present invention is to provide a machine inwhich each of the reels is movably supported on the ground by a frontroller and a rear roller with the fixed knife bar and the rotary bladeassembly being disposed between the two support rollers, and anadditional roller mounted for movement into engagement with the groundto raise the rear roller, thereby to raise the height of the fixed knifebar.

The machine of the present invention may be used for functions otherthan mowing golf greens. The reels for cutting the golf greens may beremoved and replaced by reels providing spikers or vertical cutters.

Thus, in this description and in the claims appended hereto, unlessotherwise specified, the terms reel or reel assembly" are intended torefer to a lawn maintenance device of the type including a cuttingelement which rotates about an axis generally parallel with the ground.

Other objects and features of the present invention will become apparentas this description progresses.

To the accomplishment of the above and related objects, my invention maybe embodied in the form illustrated in the accompanying drawings,attention being called to the fact, however, that the drawings areillustrative only, and that change may be made in the specificconstruction illustrated and described, so long as the scope of theappended claims is not violated.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an elevational view of themachine of the present invention with the reel assemblies shown inphantom;

FIG. 2 is a partially sectioned and cut away top view of the machine ofthe present invention with the seat removed and steering wheel removedand with the reel assemblies shown in phantom; FIG. 3 is a fragmentaryperspective view, partially exploded, showing the front frame portion ofthe vehicle with its supporting wheels and steering mechanism and armswhich support the reel assemblies;

FIG. 4 is an enlarged fragmentary sectional view of the steeringmechanism for the machine including the means for steering the frontreel assembly relative to the front frame portion;

FIG. 5 is an enlarged fragmentary view of the drive shaft andelectrically-operated clutch arrangement for driving the reels;

FIG. 6 is an elevational view, partially cut away, of a reel assembly;

FIG. 7 is an enlarged fragmentary sectional view taken along the sectionlines 77 in FIG. 6; and

FIG. 8 is a diagrammatical view showing the hydraulic controls andelectrical controls for positioning and driving the reel ssemblies.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand particularly to FIGS. 1 through 4 initially, it will be seen thatthere is illustrated th turf maintenance machine of the presentinvention, indicated generally by the reference numeral 10. The machine10 comprises a vehicle including a rear frame portion 12, front frameportion 14, rear wheels 16 movably supporting the rear frame portion,and front wheels 18 movably supporting the front frame portion. The rearwheels 16 are the drive wheels for the vehicle. It will be appreciatedthat the front frame portion 14, which is shown in perspective in FIG.3, is relatively small as compared to the'rear frame portion 12.

It will be seen that a seat 26 for the operator, fuel tank 28, engine30, hydrostatic transmission 32, battery 34, hydraulic fluid tank 36,hydraulic pump 38, and gear reduction and differential assembly 40 aremounted on and carried by the rear frame portion 12. Additionally, asteering housing and control panel 48 are disposed forwardly of the seat26 to be in front of the operator of the vehicle with a steering wheel50 mounted above the housing 48 and in front of the seat 26. Thesteering wheel 50 is mounted conventionally on a steering shaft, theupper portion 52 of which is connected to the lower portion 54 by meansof a misalignment coupling 56. The lower portion 54 extends generallyvertically downwardly while the upper portion 52 extends slightlyrearwardly toward the seat 26. Further, three valve and switch controllevers 60, 62, 64 are disposed on the housing and control panel asillustrated. 0n the left side of the housing and control panel 48 is apedal 68 for operating the reels as will be described hereinafter, andon the right-hand side of the housing and control panel is a pedal 70which is connected by a linkage 71 to the control lever for thehydrostatic transmission 32. The pedal 70, therefore, is used by theoperator to control the movement of the vehicle along the ground.

It will be appreciated that the rear wheels 16 are larger in size thanthe front wheels 18, and that the front wheels are spaced relativelyclose together while the rear wheels are axially separated to providestability.

The front frame portion 14 is formed to provide a lower, rearwardly anddownwardly curved portion 78, a forwardly extending portion 80, and anupper portion 82. A trunnion 84 is carried by the forward end of therear frame portion 12, and the front frame portion 14 is mounted on thistrunnion for pivotal movement about its axis. This trunnion, therefore,establishes the generally vertical steering axis for the vehicle andabout which the front frame portion 14 and its wheels 18 pivot relativeto the rear frame portion 12.

A generally horizontally extending trunnion 88 extends forwardly fromthe lower end of the frame portion 78 and axially between the two frontwheels 18. A bracket 90 is mounted on the forward end of the trunnion 88for pivotal movement about the axis of the trunnion, this bracketcarrying a sleeve 92. The two wheels 18 are mounted on an axle 94 whichextends axially through the sleeve 92. Thus, the two front wheels 18 canpivot together about the horizontally forwardly extending axis of thetrunnion 88, which is below the rotational axis of the wheels, to followthe terrain, i.e., to keep a constant ground pressure regardless of theterrain.

Preferably, means are provided for limiting the pivotal movement of thefront wheels 18 relative to the front frame portion 14. In theillustrative embodiment, a pair of rigid stop members 96, 98 extendsrearwardly from the sleeve 92. A rigid abutment 100 extends upwardlyfrom the trunnion 88 between the stop members 96, 98 and in the pivotalpath of the members to limit pivotal movement of the wheels. g

The forwardly extending part 80 of the front frame portion 18 is formedto provide a pair of vertically spaced apart, forwardly extendingflanges 104 having coaxially aligned perforations therein. A centralreel support 106 is pivotally connected to the flanges 104 by means of avertically extending pin 107 which extends through the flanges 104 andthe reel support. The reel support 106 includes a laterally extendinglever portion 108 which will be discussed hereinafter. As viewed in FIG.4, it will be seen that the reel support 106 pivots about a verticallyextending axis 110 which is parallel to and spaced forwardly of thesteering axis about which the front frame portion 14 pivots relative tothe rear frame portion.

First means is provided for drivingly connecting the front frame portion14 to the steering means represented by the steering wheel 50 and shafts52, 54, and second means is provided for drivingly connecting the reelsupport 106 to the said steering means. In the illustrative embodiment,first and second sprockets 116, l 18 are mounted on the shaft 54 forrotation therewith. A part circular plate concentric with the steeringaxis (trunnion 84) provides lever portions 120, 122, extendingrespectively outwardly from opposite sides of the front frame portion14, the plate being rapidly connected to the front frame portion formovement therewith. A first chain 124 having its opposite ends connectedrespectively to the distal ends of the lever portions 120, 122 anditsintermediate portion trained about the first sprocket 1 16 isprovided so that rotation of the sprocket drives the front frame portionabout the steering axis.

Another part circular plate concentric with the steering axis providessecond lever portions 128, 130 extending respectively outwardly fromopposite sides of the front frame portion, this plate (second leverportions 128, 130) being pivotally movable relative to the front frameportion as well as to the plate providing the lever portions 120, 122. Asecond drive chain 132 having its opposite ends connected respectivelyto the distal ends of the second lever portions 128, 130 and itsintermediate portion trained about the second sprocket 118 is providedso that rotation of the sprocket 118 pivots the second lever portionsabout the steering axis and relative to the front frame portion.

As viewed in FIG. 4, it will be appreciated that the lever portions 120,122 are allochirally related with the opposite end portions of the drivechains trained about the peripheries of the lever portions, and that thesecond lever portions 128, 130 are allochirally related with theopposite end portions of the second drive chain 132 trained about theperipheries of the second lever portions. As the plates pivot about thesteering axis, the chains 124, 132 wrap about one side of the plate andunwrap from the other side of the plate.

It will also be appreciated that the upper plate providing the leverportions 128, 130 is smaller than the lower plate. Thus, the firstsprocket 116, lower plate and chain 124 constitute a first transmissionfor drivingly connecting the steering shaft to the front frame portion,the first transmission providing a first speed reduction ratio, whilethe sprocket 118, the upper plate and the chain 132 provide a secondtransmission means for drivingly connecting the steering shaft to thecentral reel support 106, the second transmission means providing asecond and lower speed reduction ratio.

The upper plate 130 is drivingly connected to the lever portion 108 by arigid link means 134, the length of which is preferably adjustable sothat the position of the central reel support 106 can be adjustedrelative to the front frame portion 14. Additionally, preferably, meanssuch as the illustrated threaded connector 138, block 140 and nut 142are provided for adjusting the chains 124, 132.

The central reel support 106 is formed with generally horizontallyextending sleeves 148, 150 providing a pair of vertically spaced apart,parallel and generally horizontally extending pivot axes. A pair offorwardly extending reel supporting arms 152, 154 having their proximalends pivotally connected to the central reel support by pins 156, 158for movement respectively about the sleeve 148, 150 axes is provided. Arigid bracket 160 including a horizontally forwardly extending trunnion162 is pivotally connected to the distal ends of the arms 152, 154 bymeans of the illustrated pivot pins 164, 166. The trunnion 162 providesa horizontally forwardly extending pivot axis for the central reel 168.The pivot axes provided by the pins 164, 166 are parallel to the axes ofthe sleeves 148, 150 (pins 156, 158) and vertically spaced apart by adistance equal to the vertical distance between the axes of the sleeves.Thus, the pivot axis of the trunnion 162 remains generally horizontallyas the arms 152, 154 are raised and lowered to raise and lower thecentral reel 168.

Preferably, stop means is provided for limiting the pivotal movement ofthe reel 168 about the trunnion 162. In the illustrative embodiment,this stop means includes a stop assembly 170 including a pair offorwardly extending stop fingers, the stop assembly 170 being mountedfor pivotal movement relative to the bracket about the axis of the pin166. The illustrative stop assembly is adjustable by means such as anadjustment screw 172, the head of which engages the arm 154 to determinethe position of the fingers.

The central reel 168 is selectively raised and lowered by means of ahydraulic cylinder 176, the distal end of the piston of which isconnected to the bracket 160 as indicated at 178 and the proximal end ofthe cylinder of which is connected to the upper portion 82 as indicatedby 180. The connection made at 180, of course, must accommodate themovement of the central reel support 106 about the axis 110. Such aswivel connection can, of course, be made in a conventional manner.

As clearly shown in the enlarged view of FIG. 4, left and right reelsupports 186, 188 are disposed respectively on the left and right sidesof the front frame portion 14, the left and right reel supports beingrigidly connected to the front frame portion for pivotal movementtherewith about the steering axis of the trunnion 84. Each left andright reel support 186, 188 provides a horizontal pivot axis extendingforwardly and generally parallel to the trunnion 88, Le, perpendicularto the rotational axis of the front wheels 18. Left and right reelsupporting arms 190, 192 are provided, the arms having their proximalends pivotally connected respectively to the left and right reelsupports for movement about their said horizontally forwardly extendingpivot axes. The arm provides, at its distal end, support means 194providing a forwardly extending trunnion 196 defining a pivot axisparallel to the axis about which the arm 190 pivots. Similarly, the arm192 includes such a support means 198 providing such a trunnion 200defining a pivot axis parallel to the axis about which the arm 192pivots.

Reels 206, 208 are respectively mounted on the trunnions 196, 200 forpivotal movement about the axes of the trunnions. A hydraulic cylinder210 is provided for raising and lowering the left reel 206, the pistonbeing connected to the support 194 as indicated at 212 and the cylinderbeing connected to the upper portion 82 as indicated at 214. Similarly,a hydraulic cylinder. 216 is provided for raising and lowering the rightreel 208, the piston being connected to the support 198 as indicated at218 and the cylinder being connected to the upper portion 82 asindicated at 220.

Each of the arms 190, 192 carries stop means 222, 224 for limiting thepivotal movement of the reel 206,

208 carried thereby about the axis of the trunnion 196,

200. It will be appreciated that the stops 222, 224 are arranged suchthat when the arms 190, 192 are raised, the stops will engage the reelsto prevent them from pivoting.

Referring now particularly to FIGS. 1, 2, 5 and 8, it will be seen thatthe hydrostatic transmission 32 is drivingly connected to the engine bybelt means 230 and that the hydraulic pump 38 is drivingly connected tothe engine by means of a belt 232. Disposed forwardly of the hydrostatictransmission 32 is a jack shaft or driven shaft 234, the ends of whichare journal mounted by means of bearings 236, 238 on the frame portion12. A belt 240 is trained about a pulley 242 on the shaft 234 and apulley 244 on the input shaft of the hydrostatic transmission 32, i.e.,the shaft which is driven by the belt means 230. Thus, the shaft 234 isdrivingly connected to the engine so that the rotational speed of theshaft 234 is dependent directly on the speed of the engine; This featureallows the ground speed and the speed at which the reels are driven tobe independent. Particularly, the reels are driven from the shaft 234which rotates at a speed directly proportional to the engine speed whilethe axle 42 is driven from the hydrostatic transmission 32, the outputspeed of which is selectively variable and controlled by the pedal 70.The number of clips per inch can, therefore, be established bycontrolling the speed of the shaft 234 relative to the ground speed ofthe machine 10.

There are a flexible drive cable 250 for the left reel, a flexible drivecable 252 for the right reel and a flexible drive cable 254 for thecentral reel. The proximal end of the flexible cable 250 is drivinglyconnected to a pulley 256 which, in turn, is drivingly connected by abelt 258 to a pulley 260 on the shaft 234. The proximal end of the cable252 is drivingly connected to a pulley 262 which, in turn, is drivinglyconnected by a belt 264 to a pulley 266 on the shaft 234. Then, theproximal end of the cable 254 is drivingly connected to a pulley 268which, in turn, is drivingly connected by means of a belt 270 to apulley 272 on the shaft 234. It will be appreciated from FIG. that thepulleys 256, 258, 262 are journal mounted on brackets spaced forwardlyfrom the shaft 234.

Electrically-operated clutches 274, 276, 278 are provided forrespectively drivingly connecting the pulleys 260, 266, 273 to the shaft234 for rotation therewith. When the clutches are energized, the pulleysrotate with the shaft 234 respectively to drive the cables 250, 252,254.

Referring further to FIG. 8, the manner in which the clutches 274, 276,278 and the power cylinders 176, 210, 216 are controlled and operatedwill be discussed. A control valve 280, 282, 284 is provided fordominating each cylinder 210, 176, 216, and a master valve 286 isprovided for dominating the control valves and controlling the flow ofhydraulic fluid to the control valves. The master valve 286, which maybe a conventional 3-way valve, is operated by the foot pedal 68discussed previously. Each of the valves 280, 282, 284 may beconventional 2-way valves disposed as shown in FIG. 8 in the hydrauliclines. These control valves are operated mutually by moving the levers60, 62, 64 associated respectively therewith.

A control switch 288, 290, 282 is provided for dominating each clutch274, 278, 276 as shown in FIG. 8, and a master switch 294 is providedfor dominating the control switches and controlling the flow of currentto the control switches. Each control switch 288, 290, 292 isoperatively connected to its associated control valve 280, 282, 284 tobe operated by the operation of the control valve. Particularly, each ofthe switches 288, 290, 292 is a switch, such as a microswitch, theactuator of which is moved by some mechanism, such as the lever 60, 62,64, moving its associated control valve. Similarly, the switch 294 isoperatively connected to the master valve 286 to be operated when themaster valve is operated by depressing the pedal 68.

The purpose of the control valves 280, 282, 284 and the control switches288, 290, 292 is to determine which of the three reels 168, 206, 208will be lowered and driven during operation of the machine 10. Forinstance, if it is desired that the central reel 168 not be operative,the valve 282 and switch 290 can be operated so that, when the mastervalve 286 and 294 are operated, the central reel will not be lowered andthe clutch 278 will not be energized to drive the cable 254. If all ofthe switches 288, 290, 292 remain closed and all of the valves 280, 282,284 remain open, the reels 168, 206, 208 can be simultaneously raisedand lowered and driven when lowered by actuating the pedal 68 whichmanipulates the master valve 286 and master switch 294.

The arrangement of thepedal 68, master valve 286 and master switch 294may take different forms. One preferred form is to have the pedal, valveand switch arranged such that depressing the front half of the pedallowers the reels, and when the pedal is full forward and down, the reelsare driven (clutches are energized). Then, depressing the rear half ofthe pedal raises the reels and deenergizes the clutches to stop thereels.

Turning now to FIG. 7, the preferred reel structure will be discussed,only the reel 206 being illustrated for convenience. Further, since onlyone side of the reel is shown and discussed, it will be appreciated thatthe other side includes corresponding mounting brackets, connectingelements and the like. The reel 206 includes a frame assembly upon whicha generally conventional rotaty blade 304 is mounted for rotation aboutan axis defined by the shaft 306 supported in a plane 307, the axisextending generally parallel with the ground. Below the rotary blade 304is an axially extending fixed knife bar 308 which cooperates with therotary blade in clipping grass. The frame assembly 300 is movablysupported on a front roller 310 which rotates about an axis parallel tothe axis of the shaft 306 and which extends across the front of the reel206. The frame assembly 300 is also movably supported on a rear roller312 disposed behind the fixed knife bar 308. The roller 312 is parallelto the shaft 306 and extends across the reel 206. The front and rearrollers 310, 312, therefore, establish the height of the frame assembly300 and the fixed knife bar 308 which is carried by the frame assembly.As will be discussed hereinafter, the positions of these rollers 310,312 can be adjusted to adjust'the height of the blade 308. For example,if a green is being cut at /4 inch, the rollers 310, 312 can be adjustedto place thefixed knife bar 308 at the proper height for making a V4inch cut.

It is desirable to have collars or fringes as they are sometimes calledextending perimetrally about the greens to act as a brake to slow theroll of the golf ball. Such collars are a desirable part of allchampionship greens, and they enhance the beauty of the greens.

The height of cut on collars is, on the average, approximately twice theheight of cut of the green. For example, if the green is beingmaintained at V4 inch, then the collar would be cut at 108 inch. Sincethe machine 10 is particularly suited for maintaining greens, each reelassembly preferablyincludes an additional roller 314 journal mounted forrotation about an axis 316 which also is parallel to the axes of therollers 310,

312. Means, such as the extensibly related brackets 318, 320 is providedfor mounting the additional roller 314 for movement between a lower,ground engaging position and an upper position shown in phantom. In theillustrative embodiment, the bracket 318 swings about a horizontallyextending axis 322 so that the roller 314 can be moved from its lowerposition to its upper position. Illustratively, the position of theroller 314 may be adjustable by means of a fastening element 324extending through the bracket 318 and an elongated slot 326 in thebracket 320. The bracket 320 can be extended such that, when theadditional roller 314 is engaging the ground, the rear roller 312 islifted from the ground as illustrated to raise the fixed knife bar 308.For instance, the roller 314 can be arranged to raise the fixed knifebar 308 to make the 96 inch cut on the collar of the green.

The bracket 318 is supported by a frame element 332 extending rearwardlyfrom the frame assembly 300. The roller 314 is locked in its lower,ground engaging position by means of a pin 330 which extends intoengagement with an opening in this element 322. Referring to FIG. 7, itwill be seen that the pin 330 is disposed for reciprocation in a fitting333 attached to the bracket 318. A knob 334 is connected to the pin 330so that the pin can be pulled out of engagement with the opening in theelement 332. A spring 336 is provided for urging the pin into engagementwith the opening in the element 332.

It will be appreciated, therefore, that the roller 314 can be easilymoved into its lower, ground engaging position quickly to change (raise)the height of the cut.

The reel 206 is carried on and supported by an inverted U-shaped supportbracket 340. The trunnion 196 extends through an opening in the uppercross bar of the support 340 as suggested at the right-hand side of FIG.3.

The front roller 310 is journal mounted on forwardly extending brackets342 at the ends of the roller, these brackets 342 being respectivelypivotally connected to the distal ends of the downwardly extending legsof the support 340 as indicated at 344. The brackets 342 are rigidlyfastened by adjustment means to be described hereinafter to the frameassembly 300. Thus, the entire frame assembly 300 of the reel 206 pivotsabout the axis indicated at 344 relative to the trunnion 196. In otherwords, the reel 206 pivots about the horizontal forwardly-extending axisof the trunnion 196 as well as about the axis indicated at 344 which isperpendicular to the axis of the trunnion 196 to permit the rollers 310and 312 or 314 to follow the ground.

A hook 343 extends forwardly from the frame assembly 300 as illustratedin FIG. 6. The purpose of the hook 343 is to engage the support 340 whenthe supporting arm for the reel 206 is raised, thereby to limit pivotingof the reel about the axis indicated at 344.

The position of the frame assembly 300 relative to the roller 310 isselectively adjusted by rotating a threaded shaft 346 which threadedlyengages a block 347 which is attached to the frame assembly. The lowerend of the shaft 346 is journal mounted in a bearing 346a connected tothe bracket 342. There is a knob 348 on the upper end of the shaft 346for raising and lowering the bracket 342 relative to the block 347.Locking screws (not shown) are provided for rigidly connecting thebracket 342 to the block 347 in any selected position. These screws areloosened to effect adjustment and then tightened after adjustment.Further, a generally C-shaped bracket 352 is rigidly connected to theblock 347. Screws 354, 356 are carried by the bracket 352 as illustratedin FIG. 6 to engage a block 358 which is attached to the plate 307supporting the shaft 306 for the reel 304, i.e., the bearing for thereel 304. Adjustment of block 358, therefore, adjusts the reel 304relative to the knife bar 308 which is fixed relative to the frameassembly 300.

A locking nut 360 is threaded on a fastening element which extendsthrough the block 358 as illustrated. The block 358 is slotted to permitadjustment of the plate 307 about the axis of bolt 362. A carriage bolt364, which extends through an arcuate slot in the plate 307, is alsoloosened to accomplish the adjustment of the plate.

The position of the rear roller 312 relative to the frame assembly 300is accomplished by positioning the threaded shaft 370 which supports theroller 312. Lock nuts 372, 374 are threaded on the shaft 370 to engage,respectively, the upper and lower ends of ablock 376 connected to theframe assembly. Primarily the purpose of this adjustment is to make theaxis of the roller 312 parallel to the knife bar 308.

We have provided a driven spiral brush 367 which is journal mounted toextend parallel to the collar 312. The brush 367 engages the roller 312throughout its length and turns against the roller 312 to keep grass 7clippings from sticking to and building up on the roller. For thisreason, the brush 367 serves a very useful purpose because a build up ofgrass clippings on the roller 312 will raise the knife bar 308 anddestroy the height accuracy and smoothness of the cut.

The position of the brush 367 relative to the roller 312 may beestablished by adding and removing shims such as indicated at 368. Theseshims 368 may be added or removed to compensate for brush wear.

The build up of grass clippings on the front roller 310 is not generallyas bad as it is on the rear roller 312. Means, such as a scraper (notshown) may be used to keep the front roller clean.

What is claimed is:

1. A turf maintenance machine comprising a vehicle including a rearframe portion, a front frame portion, means for connecting said frontframe portion to said rear frame portion for pivotal movement about asteering axis, rear wheel means for movably supporting said rear frameportion, front wheel means for movably supporting said front frameportion, means for connecting said front wheel means to said front frameportion for pivotal movement about an axis extending generallyperpendicularly to the rotational axis for said front wheel means andlongitudinally of said machine whereby said front wheel means can followthe terrain of the ground, steering means for driving said front frameportion about said steering axis, a plurality of reel assemblies, meansfor connecting each said reel assembly to said front frame portion, eachsaid connecting means providing a pivot axis about which the reelassembly connected thereto pivots to follow the terrain of the ground,said pivot axis being generally parallel to the axis which said frontwheel means pivots.

2. The machine of claim 1 in which said front wheel means includes apair of axially spaced wheels journalled for rotation about saidrotational axis, said means for connecting said front wheel means tosaid front frame portion including means on said front 4. The machine ofclaim 1 in which said front wheel v means includes a pair of axiallyspaced wheels journalled for rotation about said rotational axis, saidmeans for connecting said front wheel means to said front frame portionincluding a rigid trunnion extending generally horizontally andforwardly from said front frame portion and axially between said wheels,and bracket means for supporting said wheels, said bracket meansjournalled on said trunnion, the axis of said trunnion being disposedbelow the rotational axis for said wheels.

5. The machine of claim 4 including a pair of stop members carried bysaid bracket means and an abutment member carried by said front frameportion and disposed in the pivotal path of movement of said stopmembers to limit the pivotal movement of said front wheel means relativeto said front frame portion.

6. The machine of claim 4 in which each said reel assembly connectingmeans includes a rigid depending support mounted for pivotal movement,at its upper portion, about said pivot axis, said reel assembly'beingconnected to the lower portion of said support for pivotal movementabout a second pivot axis perpendicular to said first pivot axis. 7

7. The machine of claim 1 in which each said connecting means alsoprovides a second pivot axis about which said reel assembly connectedthereto pivots to follow the terrain, the second pivot axis beingperpendicular to the first said pivot axis provided by said connectingmeans.

8. The machine of claim 1 in which each said connecting means includes arigid depending support mounted for pivotal movement at its upperportion, about said pivot axis, said reel assembly being connected tothe lower portion of said support for pivotal movement about a secondpivot axis perpendicular to said first pivot axis.

9. A turf maintenance machine comprising a vehicle including a rearframe portion, a front frame portion, means for connecting said frontframe portion to said rear frame portion for pivotal movement about asteering axis, rear wheel means for movably supporting said rear frameportion, front wheel means for movably supporting said front frameportion, said front wheel means being journal mounted on said frontframe portion for pivotal movement therewith about said steering axis,and steering means for pivoting said front frame portion about saidsteering axis, first means for drivingly connecting said front frameportion to said steering means, a central reel support, means forconnecting said reel support to said front frame portion for pivotalmovement about a second steering axis disposed forwardly of the firstsaid steering axis, and second means for drivingly connecting said reelsupport to said steering means.

10. A machine asin claim 9 in which said steering means includes asteering shaft journalled on said rear frame portion, said first meansincluding a sprocket mounted on said steering shaft for rotationtherewith, lever portions extending respectively outwardly from oppositesides of said front frame portion, said lever portions being rigidlyconnected to said front frame portion for movement therewith, and adrive chain having its opposite ends connected respectively to thedistal ends of said lever portions and its intermediate portion trainedabout said sprocket.

11. A machine as in claim 10 in which said second means includes asecond sprocket mounted on said steering shaft for rotation therewith,second lever portions extending respectively outwardly from oppositesides of said front frame portion, said second lever portions beingrigidly connected together for pivotal movement relative to said frontframe portion, a second drive chain having its opposite ends connectedrespectively to the distal ends of said second lever portions and itsintermediate portion trained about said second sprocket, and meansdrivingly connecting said central reel support to said second leverportions.

12. A machine as in claim 11 in which said first mentioned leverportions are provided by a part circular plate concentric with saidsteering axis, said lever portions of said plate being allochirallyrelated with the opposite end portions of said drive chain trained aboutthe peripheries of said lever portions, said second lever portions beingprovided by a second part circular plate concentric with said steeringaxis and pivotally movable about said steering axis relative to saidfront frame portion, said second lever portions of said second platebeing allochirally related with the opposite end portions of said seconddrive chain trained about the peripheries of said second lever portions.

13. A machine as in claim 12 in which said means drivingly connectingsaid central reel support to said second lever portions includes a leverextending rigidly outwardly from said reel support and rigid link meansconnecting the distal end of said lever to said second plate.

14. A machine as in claim 13 in which said rigid link means isselectively adjustable to position said central reel support relative tosaid front frame portion.

15. A machine as in claim 9 in which said steering means includes asteering shaft journalled on said rear frame portion and a steeringmeans for rotating said shaft, said first means including a firsttransmission means for drivingly connecting said steering shaft to saidfront frame portion, said first transmission means providing a firstspeed reduction ratio, and said second means including a secondtransmission means for drivingly connecting said steering shaft to saidcentral reel support, said second transmission means providing a secondand different speed reduction ratio.

16. A turf maintenance machine comprising a vehicle including a rearframe portion, a front frame portion, means for connecting said frameportion to said rear frame portion for pivotal movement about a steeringaxis, rear wheel means for movably supporting said rear frame portion,front wheel means for movably supporting said front frame portion, saidfront wheel means being journal mounted on said front frame portion forpivotal movement therewith about said steering axis, and steering meansfor pivoting said front frame portion about said steering axis, firstmeans for drivingly connecting said front frame portion to said steeringmeans, a central reel support, means for connecting said reel support tosaid front frame portion for pivotal movement about a second steeringaxis disposed forwardly of the first said steering axis, and secondmeans for drivingly connecting said reel support to said steering means,said central reel support extending generally forwardly from said frontframe portion, and left and right reel supports disposed respectively onthe left and right sides of said front frame portion, said left andright reel supports being rigidly connected to said front frame portionfor pivotal movement therewith about the first said steering axis.

17. The machine of claim 16 in which each of said left and right reelsupports provides a horizontal pivot axis extending generallyperpendicular to the rotational axis of said front wheel means, left andright reel supporting arms having their proximal ends pivotallyconnected respectively to said left and right reel Supports for movementabout their said pivot axes, each arm providing, at its distal end,support means providing a pivot axis parallel to the axis about whichsaid arm pivots, a reel pivotally mounted on each of said support means,and means for raising and lowering each of said arms.

18. The machine of claim 17 including a support member mounted on eachsaid support means for pivotal movement about the axis providingthereby, each said reel being pivotally connected to its associatedsupport member for movement about a second pivot axis perpendicular tothe axis of its said support means.

19. The machine of claim 18 including means for limiting the pivotalmovement of each said reel relative to its support member.

20. The machine of claim 16 in which said central reel support providesa pair of vertically spaced apart, parallel and generally horizontallyextending pivot axes, a pair of forwardly extending reel supporting armshaving their proximal ends pivotally connected to said central reelsupport for movement respectively about said pair of axes, a rigidbracket including support means providing a pivot axis, means forproviding pivotal connections between the distal ends of said arms andsaid bracket, the last said means providing pivot axes which areparallel to said pair of axes of said central reel support andvertically spaced apart by a distance equal to the vertical distancebetween said pair of axes, whereby said pivot axis of said rigid bracketremains generally horizontally as said pair of arms are raised andlowered, a central reel mounted on said rigid bracket for pivotalmovement about its said axis, and power means for raising and loweringsaid pair of arms.

21. The machine of claim 20 including a support member mounted on saidrigid bracket for pivotal movement about its said axis, said centralreel being pivotally connected to said support member for movement abouta second pivot axis perpendicular to the axis of said bracket.

22. The machine of claim 21 including means for limiting the pivotalmovement of said central reel relative to its support member.

23. The machine of claim 20 in which each of said left and right reelsupports provides a horizontal pivot axis extending generallyperpendicular to the rotational axis of said front wheel means, left andright reel supporting arms having their proximal ends pivotallyconnected respectively to said left and right reel supports for movementabout their said pivot axes, each arm providing, at its distal end,support means providing a pivot axis parallel to the axis about whichsaid arm pivots, a reel pivotally mounted on each of said support means,and power means for raising and lowering each of said arms.

24. The machine of claim 23 including a driven'shaft disposed on saidrear frame portion, a flexible cable drive for each of said left andright reels and said central reel, the distal ends of said cable drivesbeing drivingly connected respectively to said reels, and selectivelyoperable clutch means for respectively drivingly connecting the proximalends of said cable drives to said driven shaft.

25. The machine of claim 23 including stop means on each of said leftand right reel supporting arms for limiting the relative pivotalmovement of the reel mounted on the distal end thereof, and stop meanson said rigid bracket for limiting the relative pivotal movement of thecentral reel mounted thereon.

26. The machine of claim 23 including a driven shaft disposed on saidrear frame portion, a flexible cabledrive for each of said left andright reels and said central reel, the distal ends of said cable drivesbeing drivingly connected respectively to said reels, and meansincluding electrically operated clutches for respectively drivinglyconnecting the proximal ends of said cable drives to said driven shaft.

27. The machine of claim 23 including means for connecting said frontwheel means to said front frame portion for pivotal movement about agenerally horizontal axis extending generally perpendicularly to thejournal axis for said front wheel means.

28. The machine of claim 27 including stop means for limiting thepivotal movement of said front wheel means relative to said front frameportion.

29. The machine of claim 27 in which said front wheel means includes apair of axially spaced wheels journalled for rotation about saidrotational axis, said means for connecting said front wheel means tosaid front frame portion including a rigid trunnion extending generallyhorizontally and forwardly from said front frame portion and axiallybetween said wheels, and bracket means for supporting said wheels, saidbracket means being journalled on said trunnion, the axis of saidtrunnion being disposed below the rotational axis for said wheels.

30. The machine of claim 29 including a pair of stop members carried bysaid bracket means and an abutment member carried by said front frameportion and disposed in the pivotal path of movement of said stopmembers to limit the pivotal movement of said front wheel means relativeto said front frame portion.

31. The machine of claim 29 in which said steering means includes asteering shaft journalled on said rear frame portion and a steeringwheel for rotating said shaft, said first means including a firsttransmission means for drivingly connecting said steering shaft to saidfront frame portion, said first transmission means providing a firstspeed reduction ratio, and said second means including a secondtransmission means for drivingly connecting said steering shaft to saidcentral reel support, said second transmission means providing a secondand different speed reduction ratio.

" gg g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3, 7 7] 2 9 6 Dated November 13, 1973 lnv0ntor(s) Charles Eu. Sorenson,et als.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 1, line 65, "wheels" should be reels Column 3, line 22"mechanism" should be mechanisms line 34, "ssemblies" should beassemblies line 40, "th" should be the Column 5,- line 2, "rapidly"should be rigidly Column 6, line 21, "by" should be at Column 7, line38, "273" should be 272 line 54,

"mutually" should be manually line 56, "282" should be 292 Column 8,line 34, "rotaty should be rotary line 36, "plane should be plate line63, "108" should be l/2 Column 9 line 22 "322" should be 332 Column 10,line 26, "collar" should be roller line 62, (Claim 1, last line) after"axis" insert about Column ll, line 15, (Claim 4, line 9) after "means"insert being Column 12 line 53, (Claim 16 line 3) after "said" (firstoccurrence) insert front Column 13, line 22, (Claim 18, line 3)"providing" should be provided Signed and sealed this 1 3211 'day ofJune 19714..

(SEAL) Attest:

' EDWARD M.FLETCHER,JR. C. MARSHALL DANN 'Attesting Officer 1Commissioner of Patents

1. A turf maintenance machine comprising a vehicle including a rearframe portion, a front frame portion, means for connecting said frontframe portion to said rear frame portion for pivotal movement about asteering axis, rear wheel means for movably supporting said rear frameportion, front wheel means for movably supporting said front frameportion, means for connecting said front wheel means to said front frameportion for pivotal movement about an axis extending generallyperpendicularly to the rotational axis for said front wheel means andlongitudinally of said machine whereby said front wheel means can followthe terrain of the grOund, steering means for driving said front frameportion about said steering axis, a plurality of reel assemblies, meansfor connecting each said reel assembly to said front frame portion, eachsaid connecting means providing a pivot axis about which the reelassembly connected thereto pivots to follow the terrain of the ground,said pivot axis being generally parallel to the axis which said frontwheel means pivots.
 2. The machine of claim 1 in which said front wheelmeans includes a pair of axially spaced wheels journalled for rotationabout said rotational axis, said means for connecting said front wheelmeans to said front frame portion including means on said front frameportion providing a generally horizontal pivot axis for said front wheelmeans, the pivot axis extending axially between said wheels.
 3. Themachine of claim 2 including stop means for limiting the movement ofsaid front wheels about said pivot axis and relative to said front frameportion.
 4. The machine of claim 1 in which said front wheel meansincludes a pair of axially spaced wheels journalled for rotation aboutsaid rotational axis, said means for connecting said front wheel meansto said front frame portion including a rigid trunnion extendinggenerally horizontally and forwardly from said front frame portion andaxially between said wheels, and bracket means for supporting saidwheels, said bracket means journalled on said trunnion, the axis of saidtrunnion being disposed below the rotational axis for said wheels. 5.The machine of claim 4 including a pair of stop members carried by saidbracket means and an abutment member carried by said front frame portionand disposed in the pivotal path of movement of said stop members tolimit the pivotal movement of said front wheel means relative to saidfront frame portion.
 6. The machine of claim 4 in which each said reelassembly connecting means includes a rigid depending support mounted forpivotal movement, at its upper portion, about said pivot axis, said reelassembly being connected to the lower portion of said support forpivotal movement about a second pivot axis perpendicular to said firstpivot axis.
 7. The machine of claim 1 in which each said connectingmeans also provides a second pivot axis about which said reel assemblyconnected thereto pivots to follow the terrain, the second pivot axisbeing perpendicular to the first said pivot axis provided by saidconnecting means.
 8. The machine of claim 1 in which each saidconnecting means includes a rigid depending support mounted for pivotalmovement at its upper portion, about said pivot axis, said reel assemblybeing connected to the lower portion of said support for pivotalmovement about a second pivot axis perpendicular to said first pivotaxis.
 9. A turf maintenance machine comprising a vehicle including arear frame portion, a front frame portion, means for connecting saidfront frame portion to said rear frame portion for pivotal movementabout a steering axis, rear wheel means for movably supporting said rearframe portion, front wheel means for movably supporting said front frameportion, said front wheel means being journal mounted on said frontframe portion for pivotal movement therewith about said steering axis,and steering means for pivoting said front frame portion about saidsteering axis, first means for drivingly connecting said front frameportion to said steering means, a central reel support, means forconnecting said reel support to said front frame portion for pivotalmovement about a second steering axis disposed forwardly of the firstsaid steering axis, and second means for drivingly connecting said reelsupport to said steering means.
 10. A machine as in claim 9 in whichsaid steering means includes a steering shaft journalled on said rearframe portion, said first means including a sprocket mounted on saidsteering shaft for rotation therewith, lever portions extendingrespectively outwardly from opposite sides of said front frame porTion,said lever portions being rigidly connected to said front frame portionfor movement therewith, and a drive chain having its opposite endsconnected respectively to the distal ends of said lever portions and itsintermediate portion trained about said sprocket.
 11. A machine as inclaim 10 in which said second means includes a second sprocket mountedon said steering shaft for rotation therewith, second lever portionsextending respectively outwardly from opposite sides of said front frameportion, said second lever portions being rigidly connected together forpivotal movement relative to said front frame portion, a second drivechain having its opposite ends connected respectively to the distal endsof said second lever portions and its intermediate portion trained aboutsaid second sprocket, and means drivingly connecting said central reelsupport to said second lever portions.
 12. A machine as in claim 11 inwhich said first mentioned lever portions are provided by a partcircular plate concentric with said steering axis, said lever portionsof said plate being allochirally related with the opposite end portionsof said drive chain trained about the peripheries of said leverportions, said second lever portions being provided by a second partcircular plate concentric with said steering axis and pivotally movableabout said steering axis relative to said front frame portion, saidsecond lever portions of said second plate being allochirally relatedwith the opposite end portions of said second drive chain trained aboutthe peripheries of said second lever portions.
 13. A machine as in claim12 in which said means drivingly connecting said central reel support tosaid second lever portions includes a lever extending rigidly outwardlyfrom said reel support and rigid link means connecting the distal end ofsaid lever to said second plate.
 14. A machine as in claim 13 in whichsaid rigid link means is selectively adjustable to position said centralreel support relative to said front frame portion.
 15. A machine as inclaim 9 in which said steering means includes a steering shaftjournalled on said rear frame portion and a steering means for rotatingsaid shaft, said first means including a first transmission means fordrivingly connecting said steering shaft to said front frame portion,said first transmission means providing a first speed reduction ratio,and said second means including a second transmission means fordrivingly connecting said steering shaft to said central reel support,said second transmission means providing a second and different speedreduction ratio.
 16. A turf maintenance machine comprising a vehicleincluding a rear frame portion, a front frame portion, means forconnecting said frame portion to said rear frame portion for pivotalmovement about a steering axis, rear wheel means for movably supportingsaid rear frame portion, front wheel means for movably supporting saidfront frame portion, said front wheel means being journal mounted onsaid front frame portion for pivotal movement therewith about saidsteering axis, and steering means for pivoting said front frame portionabout said steering axis, first means for drivingly connecting saidfront frame portion to said steering means, a central reel support,means for connecting said reel support to said front frame portion forpivotal movement about a second steering axis disposed forwardly of thefirst said steering axis, and second means for drivingly connecting saidreel support to said steering means, said central reel support extendinggenerally forwardly from said front frame portion, and left and rightreel supports disposed respectively on the left and right sides of saidfront frame portion, said left and right reel supports being rigidlyconnected to said front frame portion for pivotal movement therewithabout the first said steering axis.
 17. The machine of claim 16 in whicheach of said left and right reel supports provides a horizontal pivotaxis extending generaLly perpendicular to the rotational axis of saidfront wheel means, left and right reel supporting arms having theirproximal ends pivotally connected respectively to said left and rightreel supports for movement about their said pivot axes, each armproviding, at its distal end, support means providing a pivot axisparallel to the axis about which said arm pivots, a reel pivotallymounted on each of said support means, and means for raising andlowering each of said arms.
 18. The machine of claim 17 including asupport member mounted on each said support means for pivotal movementabout the axis providing thereby, each said reel being pivotallyconnected to its associated support member for movement about a secondpivot axis perpendicular to the axis of its said support means.
 19. Themachine of claim 18 including means for limiting the pivotal movement ofeach said reel relative to its support member.
 20. The machine of claim16 in which said central reel support provides a pair of verticallyspaced apart, parallel and generally horizontally extending pivot axes,a pair of forwardly extending reel supporting arms having their proximalends pivotally connected to said central reel support for movementrespectively about said pair of axes, a rigid bracket including supportmeans providing a pivot axis, means for providing pivotal connectionsbetween the distal ends of said arms and said bracket, the last saidmeans providing pivot axes which are parallel to said pair of axes ofsaid central reel support and vertically spaced apart by a distanceequal to the vertical distance between said pair of axes, whereby saidpivot axis of said rigid bracket remains generally horizontally as saidpair of arms are raised and lowered, a central reel mounted on saidrigid bracket for pivotal movement about its said axis, and power meansfor raising and lowering said pair of arms.
 21. The machine of claim 20including a support member mounted on said rigid bracket for pivotalmovement about its said axis, said central reel being pivotallyconnected to said support member for movement about a second pivot axisperpendicular to the axis of said bracket.
 22. The machine of claim 21including means for limiting the pivotal movement of said central reelrelative to its support member.
 23. The machine of claim 20 in whicheach of said left and right reel supports provides a horizontal pivotaxis extending generally perpendicular to the rotational axis of saidfront wheel means, left and right reel supporting arms having theirproximal ends pivotally connected respectively to said left and rightreel supports for movement about their said pivot axes, each armproviding, at its distal end, support means providing a pivot axisparallel to the axis about which said arm pivots, a reel pivotallymounted on each of said support means, and power means for raising andlowering each of said arms.
 24. The machine of claim 23 including adriven shaft disposed on said rear frame portion, a flexible cable drivefor each of said left and right reels and said central reel, the distalends of said cable drives being drivingly connected respectively to saidreels, and selectively operable clutch means for respectively drivinglyconnecting the proximal ends of said cable drives to said driven shaft.25. The machine of claim 23 including stop means on each of said leftand right reel supporting arms for limiting the relative pivotalmovement of the reel mounted on the distal end thereof, and stop meanson said rigid bracket for limiting the relative pivotal movement of thecentral reel mounted thereon.
 26. The machine of claim 23 including adriven shaft disposed on said rear frame portion, a flexible cable drivefor each of said left and right reels and said central reel, the distalends of said cable drives being drivingly connected respectively to saidreels, and means including electrically operated clutches forrespectively drivingly connecting the proximal ends of said cable drivesTo said driven shaft.
 27. The machine of claim 23 including means forconnecting said front wheel means to said front frame portion forpivotal movement about a generally horizontal axis extending generallyperpendicularly to the journal axis for said front wheel means.
 28. Themachine of claim 27 including stop means for limiting the pivotalmovement of said front wheel means relative to said front frame portion.29. The machine of claim 27 in which said front wheel means includes apair of axially spaced wheels journalled for rotation about saidrotational axis, said means for connecting said front wheel means tosaid front frame portion including a rigid trunnion extending generallyhorizontally and forwardly from said front frame portion and axiallybetween said wheels, and bracket means for supporting said wheels, saidbracket means being journalled on said trunnion, the axis of saidtrunnion being disposed below the rotational axis for said wheels. 30.The machine of claim 29 including a pair of stop members carried by saidbracket means and an abutment member carried by said front frame portionand disposed in the pivotal path of movement of said stop members tolimit the pivotal movement of said front wheel means relative to saidfront frame portion.
 31. The machine of claim 29 in which said steeringmeans includes a steering shaft journalled on said rear frame portionand a steering wheel for rotating said shaft, said first means includinga first transmission means for drivingly connecting said steering shaftto said front frame portion, said first transmission means providing afirst speed reduction ratio, and said second means including a secondtransmission means for drivingly connecting said steering shaft to saidcentral reel support, said second transmission means providing a secondand different speed reduction ratio.